1. Technical Field
This invention relates to a fixing unit and an image forming apparatus.
2. Related Art
In an image forming apparatus of a printer, a copier, a facsimile, etc., an unfixed image developed in a developer and formed is transferred to a record medium of a sheet of paper, etc., and the transferred unfixed image is heated, pressed, and fixed on the record medium in a fixing unit, thereby forming an image of a character, a pattern, a design, a photo image, etc.
As a fixing unit used with the image forming apparatus, the following belt fixing unit exists: This belt fixing unit includes a heat rotation body of a roll form, etc., heated by heating means and rotated, an endless belt for coming in contact with the outer peripheral surface portion along the rotation axis direction of the heat rotation body for rotation, and a pressing member for pressing the endless belt against the outer peripheral surface portion of the heat rotation body to form a press contact part for allowing the record medium with the unfixed image held thereon to pass through the nip (press contact part) between the heat rotation body and the endless belt.
In this type of belt fixing unit, the record medium with the unfixed image held thereon is introduced and is allowed to pass through the press contact part formed between the heat rotation body and the endless belt, whereby the unfixed image is heated, pressed, and fixed on the record medium.